All across the world, governments are rethinking their attitudes towards the criminalisation of weed. Yet in Britain, fusty politicians terrified by that video of Jon Snow losing his mind on super-skunk are refusing to free the weed, uncurb the herb or liberate the oregano dream pipe.

We went along to Hyde Park to join London’s most ardent weed advocates for the annual 4/20 celebrations, which this year doubled as a protest rally for those who want weed to be legalised.

We caught up with Big Narstie, watched the police make an array of arrests, talked to some of the activist-stoners and found out why you should always smoke through an Eric Cartman bong.